Apparatus for testing the brakes of vehicles



Oct. 9, 1934. I E PlQUEREz l I 1,976,632

APPARATUS FOR TESTING THE BRAKES OF VEHICLES Fileddlprill.v ,12; 1952 3 Sheets-Sheet l pag.1.

' 5 `\6 2'; 5 #wfg/V7054 EMILEP/qumfz Oct. 9, 1934. E, PIQUEREZ 1,976,632

APPARATUS FOR TESTlNG THE BRAKES OF VEHICLES Filed.April l2. 1932 3 Sheets-Sheet 2 F ig. 4m

Eggs-iu-- 1- l /N VE N TOR Eff/LE P/qz/E/fz 4 oct. 9, 1934. E. PlQUEREz 1,976,632

APPARATUS FOR TESTING THE BRAKES OF'v VEHICLES .By WA4/iwi Patented Oct. 9, 1934 UNITED -sT-ATES 1,976,632 v y m y m APPARATUS FOR TESTING' THE BRAKES oF v vEHIcLEs f t Emile Piquerez, Paris,-France',assignor to Tecale-f l mit Limited, Brentford, England, a? British 'v *TL cmpaflly Application April 12, 1932, serial No. 604,711 In France April 13, 1931 Claims.

An application has been filed in France, the 13th April 1931.`

In the specification of patent application Serial No. 473,670, led August ,7, 1930, there is de- 1 `5jscribed an apparatus giving, by direct. reading, the value of the ratio of the braking effort at the rimto the Weight sup' ported by the Wheel. In order to obtain that measurement, the Wheel is mounted on a carriage rolling on ramps of variable slope. After the yapplication of the brakes,ahorizont`al traction is 15V exerted on the axle of the Wheel, which transmits thateffort to the carriage. The measurementjof the coeicient K results from the determination` ofA the slope' of the ramps at the moment when the effort necessary to cause the carriage to zogmove is equal to the' braking effort and, consequently, at the moment when, the wheel com' Figs. 1 to 3 are diagrammatic views showing -the various forces and their angles of application. Only the elements of the structure which are necessary to show these forces andvangles are shown theren. v

Figsfi to 6 are views of the actual `structure of 40the device. t, Y Y To that end, as shown in the diagram in Fig. 1 of the annexed drawings, according to the present invention each carriage is provided with adevice operated mechanically and exercising at the rim of the Wheel a continuous efort (F,'Fig. 1) causing the Wheel to turhlin spite of the action of the brake. The said device, which forms part of the carriage, is arranged in such a manner that the reaction opposed by the Wheel is exercised horizontally and gives rise to a force R tending to drive the carriage in a reverse kdirection to the movement of thevwheel. ,Y

The carriage Willtakeup a position of equilibrium on its ramps at a pointtof Which the in-N .clination is ne and the equation of equilibrium Will (01773-51), v l l of the carriage itself.

From rthat equation there' is drawnj ,infsaid application No. 473,670 the relation K=Fi=mtlan afl-'g tanta tan a,

librium then 'becomes 86:-

F+f =F+lw tant: (Pirlo) tana A from whichlirnmediately results: z y

Yj `S5^ K :lg V=tan a As in said application No. I173,670, K is given by an index displaced on a -plate in relation to the movement of the carriage considered.

TheY diagram shown in Figure `2 shovvs means for carrying out the abovel method. A lever LA articulated at O, carriesa Weight vP at a distance from 06:1. This leverpresses on a stop b of` the carriage at a distance from O=p.'r y 95 g The action of the lever is ngured by the force f.

When the carriage is immovable, We A-have fp cos 0=pr sin @from which:

, As thefl-neardisplacement d of the stop b and ofv the roller arev equal, if by construction one-r 'cheeks 3 of a carriage, which is provided at its :Between two successive carriages a small plat- Figure 3 shows, diagrammatically, an approxi-v mate solution which consists `in causing to act on each carriage in movement, through the intermediary of an oscillating lever provided withl two arms at right angles to each other, a spring T whose initial tension is equal to w and r being the arms of the lever, and being equal to the radius of the ramp, as previously described.

At rest, the line of action of the spring passesthrough the point vof articulation of the lever and there is no action on the carriage.

If T were constant and horizontal the conditions would be the same as in the preceding construction. In practice T decreases slightly but theequilibrium canbe considered as sufcient.

Other diierent characteristics of the invention will be referred to in the description which follows with reference to Figures 4 to 6 of the annexed drawings, which show one form of the invention comprising the above solution for the compensation of the weight of the carriage.

Fig. l4 is a longitudinal diagrammatic view of one'endV portion of the whole of the apparatus;

Fig. 4a'is a longitudinal diagrammatic view' of the other end portion of the apparatus;

Fig. 5 shows the carriage in detail; and

Fig. 6 is a transverse sectional view onthe line 6-6 in Fig. 5.l

As shown in the drawings, each wheel 1 of the vehicle whose brakes are to be tested rest on the channelled rollers 2 mounted between the extremities with rollers 4 capable of running on curved ramps 5 integral with a frame 6 made from T irons. Y

There are thus four carriages aligned in pairs.

form 7, integral with the iixed frame, and a ramp 8, permitting access to each of the carriages, are provided.

Onthe shaft 9 of each roller or channeled ,cylinder a toothed wheel 10 is mounted, and all `on the carriage so that the system formed by the rollersandtheir drive are displaced as a whole with the carriage.

On each of the two cheeks 3 of each carriage'a continuous angle iron 14 is fixed and these two angle irons 14 carry at each end a small platform 15, 16 at the level of the channeled rollers, which complete the arrangement and allow the vehicle to be positioned on the apparatus.

" Under each of the angle irons14, which overf hang the chain transmission, are fixed shoes `roller type, it will be understood that no distri-j i' a xed point 24 on the frame 6, acts. When at mental friction can result from this arrangement.

Each of the cheeks 3 of each carriage carries at its exterior a iiat stop 18 against which is arranged a roller 19v mounted at the extremity of the arm 20 of a lever pivoted at 21 on an axle carried by the xed frame 6. This lever is provided with another arm 22, perpendicular to the preceding, on which a spring 23 attached at rest, the yarm 22 and theA spring are directed along a horizontal line passing through the axis 21 so that the action of the spring on the carriage is nil. The weight of the carriage being equal to w, the weight which each spring must compensate is equal to Each of the two springs of each carriageis thus Agiven an initialtension equal to w p n 2 r f. p being the length of the arm 20 equal to the 100 radius of the ramps 5, and r' the length of the arm 22. At the side of its attachment 24 each spring comprises a usual screw adjustment in order to permit of the regulation ofthe spring` tension. Y 1

As in said application No. 473,670, at any point of each carriage, by a cable 25, which leads to, a box 26 mounted on a. column 27, anindex 28, pulled down by a spring at the end of said cable' is Vdisplaceable in front of suitable graduations.

`When the vehicle has been mounted onthe fourcarriages Vof, the apparatus, the wheels resting on the channelled rollers 2, one ofthe axles is connected by a hook 29, to aiixed point 30 of the frame. '115 The brakes either of two wheels of the'same train, front or rear, or the four wheels simultaneously, arelocked. The motors of the carriages of the locked wheels are then started. The said wheels begin to turn and the carriagesadvance along the ramps 5, thus allowing the index to be raised in the box 26. At the moment when one of the carriages advances, the lever 20--22 can oscillate and the spring 23 acts on the carriage in the same direction as `the reaction of the Wheel, so that when the carriage is stopped, equilibrium being' attained, the corresponding index eiectively marks the braking coefficient K, by virtue of the actionexplained above.

An examination of the plate 26 thus gives all the elements necessary to carry `out the ad?,- justment of the brakes in any desired conditions.

I claim;

1. In an apparatus'for testing the brakes ofra` vehicle, `the combination of a base, a series of curved ramps mounted on said base,a' free1y mov.- able carriage for each vehicle'wheelindependently positioned on said ramps, continuously rotatingrollers on said carriages in contact with saidv vehicle wheel, means for maintaining said vehicle' stationary, and means for compensating v the weight of said Vcarriages on said ramps.

2. In an apparatus for testingv the brakes of a vehicle, the combination of a freely movable carriage for each vehicle wheel positioned on rigid,`V curved ramps, a plurality of closely disposedconf, tinuously rotating Yrollers on said `carriages form-L ing horizontal seating surfaces in contact with said vehicle wheels, means f or maintaining-said vehicle stationary, and means'for indicating the "150 maximum slope on Which the vehicle could be held by its brakes as determined by the ascension of the carriages on said ramps.

3. In an apparatus for testing the brakes of a vehicle, the combination of a freely movable carriage for each vehicle Wheel positioned on rigid, curved ramps, continuously rotating rollers on said carriages in contact with said vehicle Wheels, means for maintaining said vehicle stationary, means for compensating the Weight of said carriages on said ramps, and means for indicating the maximum slope on which the vehicle could be held by its brakes as determined by the ascension of the carriages on said ramps.

4. In an apparatus for testing the brakes of Vehicle, the combination of a freely movable carriage for each vehicle Wheel, positioned on rigid, curved ramps, a plurality of horizontally positioned rollers on said carriages for Contact with said vehicle Wheels, toothed Wheels integral with said rollers, a motor mounted on each of said carriages, a common chain connecting said motor with said toothed wheels for rotating said rollers,

Wheels are carried during testing, means for ro-y tating said rollers, whereby the carriages ascend the ramps according to the braking force of their corresponding wheels, means for indicating the braking effect of each Wheel as determined by the ascension of its carriage, means for compensating the Weight of each carriage, said means comprising a lever for each carriage each pivotally attached to the frame at one end and at their other ends abutting their carriages, and means for exerting a force opposing the influence of gravity on the carriages equal to said gravity influence. EMILE PIQUEREZ. 

